Na+/H+-exchanger-1 inhibition counteracts diabetic cataract formation and retinal oxidative-nitrative stress and apoptosis

The Na?-H?-exchanger-1 (NHE-1) controls intracellular pH and glycolytic enzyme activities, and its expression and activity are increased by diabetes and high glucose. NHE-1-dependent upregulation of the upper part of glycolysis, under conditions of inhibition (lens) or insufficient activation (retina) of glyceraldehyde 3-phosphate dehydrogenase, underlies diversion of the excessive glycolytic flux towards several pathways contributing to oxidative stress, a causative factor in diabetic cataractogenesis and retinopathy. This study evaluated the role for NHE-1 in diabetic cataract formation and retinal oxidative stress and apoptosis. Control and streptozotocin-diabetic rats were maintained with or without treatment with the NHE-1 inhibitor cariporide (Sanofi-Aventis, 10 mgkg-1d-1) for 3.5 months. In in vitro studies, bovine retinal pericytes and endothelial cells were cultured in 5 or 30 mM glucose, with or without 10 μM cariporide, for 7 days. A several-fold increase of the by-product of glycolysis, α-glycerophosphate, indicative of activation of the upper part of glycolysis, was present in both rat lens and retina at an early (1-month) stage of streptozotocin-diabetes. Cariporide did not affect diabetic hyperglycemia and counteracted lens oxidative-nitrative stress and p38 MAPK activation, without affecting glucose or sorbitol pathway intermediate accumulation. Cataract formation (indirect ophthalmoscopy and slit-lamp examination) was delayed, but not prevented. The number of TUNEL-positive cells per flat-mounted retina was increased 4.4-fold in diabetic rats (101 ± 17 vs. 23 ± 8 in controls , P<0.01), and this increase was attenuated by cariporide (45 ± 12, P<0.01). Nitrotyrosine and poly(ADP-ribose) fluorescence and percentage of TUNEL-positive cells were increased in pericytes and endothelial cells cultured in 30 mM glucose, and these changes were at least partially prevented by cariporide. In conclusion, NHE-1 contributes to diabetic cataract formation, and retinal oxidative-nitrative stress and apoptosis. The findings identify a new therapeutic target for diabetic ocular complications.     

Bax is increased in the retina of diabetic subjects and is associated with pericyte apoptosis in vivo and in vitro

Diabetes of even short duration accelerates the death of capillary cells and neurons in the inner retina by a process consistent with apoptosis. We examined whether the process is accompanied by changes in the expression of endogenous regulators of apoptosis. In postmortem retinas of 18 diabetic donors (age 67 +/- 6 years, diabetes duration 9 +/- 4 years) the levels of pro-apoptotic Bax were slightly, but significantly, increased when compared with levels in 20 age-matched nondiabetic donors (P = 0.04). In both groups, Bax localized to vascular and neural cells of the inner retina. Neither pro-apoptotic Bcl-X(S), nor pro-survival Bcl-X(L) appeared affected by diabetes. The levels of these molecules could not be accurately quantitated in lysates of retinal vessels because of variable degrees of glial contamination. However, studies in situ showed in several pericytes, the outer cells of retinal capillaries, intense Bax staining often in conjunction with DNA fragmentation. Bovine retinal pericytes exposed in vitro to high glucose levels for 5 weeks showed elevated levels of Bax (P = 0.03) and increased frequency of annexin V binding, indicative of early apoptosis. Hence, human diabetes selectively alters the expression of Bax in the retina and retinal vascular pericytes at the same time as it causes increased rates of apoptosis. The identical program induced by high glucose in vitro implicates hyperglycemia as a causative factor in vivo, and provides a model for establishing the role of Bax in the accelerated death of retinal cells induced by diabetes.     

The role of aldose reductase inhibition in diabetic neutrophil phagocytosis and killing.

This study examines whether an aldose reductase inhibitor (statil, ICI) can enhance neutrophil oxidative killing by diabetic neutrophils. We have examined a radiometric assay of phagocytosis and killing of Candida albicans by neutrophils from 20 controls and 20 subjects with insulin-dependent diabetes under various in vitro glucose concentrations. Glucose was present at 5, 10 and 20 mM in the presence and absence of statil (11 microM). Phagocytosis was unaffected by raised glucose levels in controls and in diabetic subjects. Killing by the diabetic cells was inhibited by increasing concentrations of glucose, killing was 18.9 +/- 2.0, 16.9 +/- 2.4 and 14.8 +/- 2.0% (mean +/- s.e.m.) at 5, 10 and 20 mM glucose, respectively (P less than 0.05). With the addition of statil under the same conditions killing improved to 19.3 +/- 2.0, 23.2 +/- 2.2 and 23.6 +/- 2.4 (P less than 0.01), these values were similar to the controls (P greater than 0.01). We conclude therefore that aldose reductase inhibition restores oxidative killing to normal.     

Methylglyoxal induces apoptosis mediated by reactive oxygen species in bovine retinal pericytes

One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive alpha-dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 microM) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kappaB activation and increased caspase-3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF-kappaB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kappaB are involved in the apoptotic process.     

Glucose inhibition of human fibroblast proliferation and response to growth factors is prevented by inhibitors of aldose reductase

Diabetes mellitus is associated with premature senescence of cultured dermal fibroblasts. The present study investigated the effect of elevated glucose concentrations on cultured human fibroblasts from normal donors. Mean population doubling times, population doublings until senescence, saturation density at confluence (cells/cm2), tritiated thymidine incorporation, and response to platelet-derived growth factor (PDGF) were inhibited with the increasing glucose concentrations (11.0, 22, 44, or 55 mM glucose) (P less than 0.05). Replicative life span was markedly diminished by multiple passages in high glucose medium (5.5 mM glucose: 62.4 +/- 7.9 population doublings; 22 mM glucose: 22.8 +/- 3.4 population doublings: P less than 0.05). Aldose reductase activity was present in the cultured fibroblasts (3.9 +/- 0.5 nmol/min per mg protein), and inhibitors of aldose reductase, including sorbinil (10(-4) M--10(-6) M) and tolrestat (10(-6) M--10(-8) M), completely prevented glucose-mediated inhibition of fibroblast proliferation, restored the response to PDGF, and allowed a normal replicative life span. Myo-inositol (11 microM--5.5 mM) also reversed the adverse effects of glucose. These in vitro data demonstrate that elevated concentrations of glucose inhibit cell growth and promote premature senescence, effects which can be prevented with inhibitors of aldose reductase or supplemental myo-inositol. These aldose reductase-related effects may explain the impaired growth and premature senescence of cultured connective tissue from diabetic patients.     

Regeneration and repair of myelinated fibers in sural-nerve biopsy specimens from patients with diabetic neuropathy treated with sorbinil

There is reason to believe that diabetic neuropathy may be related to the accumulation of sorbitol in nerve tissue through an aldose reductase pathway from glucose. Short-term treatment with aldose reductase inhibitors improves nerve conduction in subjects with diabetes, but the effects of long-term treatment on the neuropathologic changes of diabetic neuropathy are unknown. To determine whether more prolonged aldose reductase inhibition reverses the underlying lesions that accompany symptomatic diabetic peripheral polyneuropathy, we performed a randomized, placebo-controlled, double-blind trial of the investigational aldose reductase inhibitor sorbinil (250 mg per day). Sural-nerve biopsy specimens obtained at base line and after one year from 16 diabetic patients with neuropathy were analyzed morphometrically in detail and compared with selected electrophysiologic and clinical indexes. In contrast to patients who received placebo, the 10 sorbinil-treated patients had a decrease of 41.8 +/- 8.0 percent in nerve sorbitol content (P less than 0.01) and a 3.8-fold increase in the percentage of regenerating myelinated nerve fibers (P less than 0.001), reflected by a 33 percent increase in the number of myelinated fibers per unit of cross-sectional area of nerve (P = 0.04). They also had quantitative improvement in terms of the degree of paranodal demyelination, segmental demyelination, and myelin wrinkling. The increase in the number of fibers was accompanied by electrophysiologic and clinical evidence of improved nerve function. We conclude that sorbinil, as a metabolic intervention targeted against a specific biochemical consequence of hyperglycemia, can improve the neuropathologic lesions of diabetic neuropathy.     

抗氧化剂对系膜细胞醛糖还原酶活性的影响

目的：观察抗氧化剂对高糖培养下肾小球系膜细胞(MC)内醛糖还原酶(AR)活性的影响，探讨抗氧化剂治疗糖尿病并发症的分子机制。方法:将牛肾小球系膜细胞培养于含高糖的培养基中3周，同时加入抗氧化剂过氧化物酶和DMSO，采用间接法观察抗氧化剂对细胞内醛糖还原酶活性的影响结果:高糖作用下系膜细胞内山梨醇含量增加，表明醛糖还原酶活性增高，而抗氧化剂能抑制醛糖还原酶活性的增高。结论:氧化应激和多元醇通路关系密切，抗氧化剂通过降低AR的活性和清除多元醇通路中产生的氧自由基而对糖尿病并发症有治疗作用，为临床运用尤其是早期运用抗氧化剂治疗糖尿病提供了理论依据。     

Angiotensin II stimulates platelet-derived growth factor-B gene expression in cultured retinal pericytes through intracellular reactive oxygen species generation

Platelet-derived growth factor-BB (PDGF-BB) is a potent mitogen and chemoattractant for microvascular endothelial cells and glial cells in the retina and is thus involved in the development of proliferative diabetic retinopathy. However, relatively little is known about the regulation of PDGF-B gene expression in retinal cells. In this study, we cloned partial complementary DNAs (cDNAs) encoding bovine PDGF-B and examined the effects of angiotensin II (Ang II), which is also implicated in the pathogenesis of diabetic retinopathy, on PDGF-B gene expression in bovine cultured retinal pericytes. Ang II was found to up-regulate PDGF-B messenger RNA (mRNA) levels in bovine retinal pericytes. Telmisartan, a newly developed Ang II type 1 receptor antagonist, or an antioxidant N-acetylcysteine significantly inhibited PDGF-B gene induction in Ang II-exposed pericytes. The present results suggest that Ang II-type 1 receptor interaction could stimulate PDGF-B gene expression in cultured retinal pericytes through intracellular reactive oxygen species generation and could thus be involved in the progression of diabetic retinopathy.     

Evaluation of the peroxynitrite decomposition catalyst Fe(III) tetra-mesitylporphyrin octasulfonate on peripheral neuropathy in a mouse model of type 1 diabetes

Whereas the important role of free radicals in diabetes-associated complications is well established, the contributions of the highly reactive oxidant peroxynitrite have not been properly explored. The present study used a pharmacological approach to evaluate the role of peroxynitrite in peripheral diabetic neuropathy. Control and STZ-diabetic mice were maintained with or without treatment with the potent peroxynitrite decomposition catalyst Fe(III) tetramesitylporphyrin octasulfonate (FeTMPS), at doses of 5 or 10 mg/kg/day in the drinking water for 3 weeks after an initial 3 weeks without treatment. Mice with a 6-week duration of diabetes developed clearly manifest motor (MNCV) and sensory nerve conduction velocity (SNCV) deficits, thermal hypoalgesia (paw withdrawal, tail-flick, and hot plate tests), mechanical hypoalgesia (tail pressure Randall-Sellito test), tactile allodynia (flexible von Frey filament test), and approximately 44% loss of intraepidermal nerve fibers. They also had increased nitrotyrosine and poly(ADP-ribose) immunofluorescence in sciatic nerve, grey matter of the spinal cord, and dorsal root ganglion neurons. FeTMPS treatment alleviated or essentially corrected (at a dose of 10 mg/kg/day) MNCV and SNCV deficits, and was associated with less severe small sensory nerve fiber dysfunction and degeneration. Nitrotyrosine and poly(ADP-ribose) immunofluorescence in sciatic nerve, spinal cord, and dorsal root ganglion neurons in peroxynitrite decomposition catalyst-treated diabetic mice was markedly reduced. In conclusion, peroxynitrite contributes to large motor, large sensory, and small sensory fiber neuropathy in streptozotocin-diabetic mice. The findings provide rationale for development of potent peroxynitrite decomposition catalysts for the treatment of diabetic neuropathy.     

Polyol Pathway Mediates Enhanced Degradation of Extracellular Matrix Via p38 MAPK Activation in Intervertebral Disc of Diabetic Rats

The aim of this study was to determine the significance of diabetes on degradation of intervertebral disc (IVD) extracellular matrix. Diabetic rats showed a significant increase in glucose and sorbitol contents in the IVD. The levels of aldose reductase, p38 and metalloproteinases, and degradation of metalloproteinase-derived aggrecan and type II collagen were increased, while tissue inhibitors of metalloproteinases levels were decreased in the IVD of diabetic rats. These changes were markedly affected by inhibition of aldose reductase or p38. Diabetes might contribute to enhanced matrix degradation in the IVD and the polyol pathway might mediate this process via p38 activation.     

Depletion of substance P and calcitonin gene-related peptide in sciatic nerve of rats with experimental diabetes; effects of insulin and aldose reductase inhibition.

This study was designed to determine whether deficient substance P in the sciatic nerve of diabetic rats was associated with a similar reduction in calcitonin gene-related peptide and whether the depletion of either or both peptides could be affected by insulin treatment or by aldose reductase inhibition. Substance P and calcitonin gene-related peptide were measured as immunoreactivities in the same nerve extracts. The sciatic nerve content of substance P was significantly reduced in diabetic rats (0.063 +/- 0.011; all data are mean +/- 1 standard deviation in ng peptide/mg nerve protein; n = 9 for all groups) compared to controls (0.093 +/- 0.026). The calcitonin gene related peptide content was similarly reduced (2.14 +/- 0.49) compared to controls (3.78 +/- 1.21). Tight glycaemic control with insulin prevented completely the deficit in both peptides (substance P = 0.096 +/- 0.021, calcitonin gene-related peptide = 4.66 +/- 0.92). Treatment with the aldose reductase inhibitor, imirestat, corrected the substance P deficit (0.08 +/- 0.018) and attenuated the calcitonin gene-related peptide (3.55 +/- 1.03) depletion seen in the untreated diabetic animals. This indicates that the polyol pathway may play a role in the peptide status of the sciatic nerve. Regression analysis of all data gave r2 = 0.53, indicating a comparable effect of diabetes and the treatments on both peptides.     

Novel protective properties of IGFBP-3 result in enhanced pericyte ensheathment, reduced microglial activation, increased microglial apoptosis, and neuronal protection after ischemic retinal injury

This study was conducted to determine the perivascular cell responses to increased endothelial cell expression of insulin-like growth factor binding protein-3 (IGFBP-3) in mouse retina. The contribution of bone marrow cells in the IGFBP-3-mediated response was examined using green fluorescent protein-positive (GFP(+)) adult chimeric mice subjected to laser-induced retinal vessel occlusion injury. Intravitreal injection of an endothelial-specific IGFBP-3-expressing plasmid resulted in increased differentiation of GFP(+) hematopoietic stem cells (HSCs) into pericytes and astrocytes as determined by immunohistochemical analysis. Administration of IGFBP-3 plasmid to mouse pups that underwent the oxygen-induced retinopathy model resulted in increased pericyte ensheathment and reduced pericyte apoptosis in the developing retina. Increased IGFBP-3 expression reduced the number of activated microglial cells and decreased apoptosis of neuronal cells in the oxygen-induced retinopathy model. In summary, IGFBP-3 increased differentiation of GFP(+) HSCs into pericytes and astrocytes while increasing vascular ensheathment of pericytes and decreasing apoptosis of pericytes and retinal neurons. All of these cytoprotective effects exhibited by IGFBP-3 overexpression can result in a more stable retinal vascular bed. Thus, endothelial expression of IGFBP-3 may represent a physiologic response to injury and may represent a therapeutic strategy for the treatment of ischemic vascular eye diseases, such as diabetic retinopathy and retinopathy of prematurity.     

Diabetic retinopathy: mitochondrial dysfunction and retinal capillary cell death

Oxidative stress is increased in the retina in diabetes; the levels of oxidatively modified DNA and nitrosylated proteins are elevated, and antioxidant defense enzymes are impaired. The levels of superoxides are elevated in the retina, and the mitochondria become dysfunctional with proapoptotic protein, Bax, translocating from the cytosol into the mitochondria, and cytochrome c leaking out from the mitochondria. This is accompanied by increased retinal capillary cell apoptosis, and the formation of acellular capillaries and pericyte ghosts, the early signs of retinopathy in animal models of diabetic retinopathy. Inhibition of superoxides inhibits glucose -induced mitochondrial dysfunction, activation of caspase-3, and cell death in retinal capillary cells. In animal models, long-term administration of lipoic acid or other antioxidants inhibits the development of diabetic retinopathy via inhibition of accumulation of oxidatively modified DNA and nitrotyrosine and capillary cell apoptosis in the retina. Understanding the role of mitochondria in the development of retinopathy in diabetes should help identify therapies that can neutralize superoxides and inhibit their dysfunction and, ultimately, the development of retinopathy.     

Myo-inositol normalizes decreased sodium permeability of the blood-brain barrier in streptozotocin diabetes

The effect of a dietary supplement of an aldose reductase inhibitor (ponalrestat) or of myo-inositol on sodium transport into the rat brain and on concentrations of saccharide and polyols in cortical brain tissue and sciatic nerve was investigated in control rats and in streptozotocin-diabetic rats after a diabetes duration of 2 weeks. In untreated diabetes, the neocortical blood-brain barrier permeability for sodium decreased by 28% (3.4 +/- 0.4 vs 4.7 +/- 1.6 x 10(-5) ml/s g, mean +/- SD) as compared to controls. Levels of glucose, sorbitol and fructose increased in brain as well as in nerve tissues, whereas myo-inositol depletion was not demonstrable. Ponalrestat treatment of diabetic animals had no effect upon the decreased neocortical blood-brain barrier permeability to sodium (3.5 +/- 0.9 vs 4.7 +/- 1.1 x 10(-5) ml/s g) despite normalization of brain and nerve content of sorbitol and fructose. Myo-inositol supplementation of diabetic rats normalized sodium passage into the brain (4.2 +/- 1.1 vs 4.4 +/- 0.5 x 10(-5) ml/s g). Brain concentrations of monosaccharides and polyols were normalized as compared to the myo-inositol treated control group and nerve concentrations of glucose, sorbitol, and fructose were significantly increased. Myo-inositol treatment leads to a normalization of blood-brain barrier permeability; it is suggested that myo-inositol exerts a restituting effect upon Na+/K+-ATPase activity of the cerebral endothelial cells.     

Administration of an aldose reductase inhibitor, ONO-2235, to streptozotocin-diabetic mice restores reductions of DRG neuronal attachment to extracellular matrix proteins in vitro

Attachments of cultured dorsal root ganglion (DRG) neurons to the extracellular matrix (ECM) proteins (type I and IV collagens, laminin and fibronectin) and the adhesion ligand arginine-glycine-aspartic acid (RGD) were impaired in mice 2 weeks after the induction of diabetes by streptozotocin (STZ). However, administration of the aldose reductase inhibitor, ONO-2235, to the STZ-diabetic mice for 1 week restored DRG neuronal attachment to the ECM proteins and RGD to a level close to normal mice. These results suggest that activation of the aldose reductase and subsequent metabolic disorders in diabetic animals may play an important role in detrimental alterations of the neuronal cell-surface receptors for the ECM proteins.     

Effects of long‐acting somatostatin analogues on redox systems in rat lens in experimental diabetes

The effects of long‐acting somatostatin analogues, angiopeptin (AGP) and Sandostatin (SMS), on the early decline in the lens content of glutathione (GSH), ATP and NADPH and increase in sorbitol were studied in STZ diabetic rats, and comparison was made with the effect of insulin. Three factors prompted this study: (i) the known increase in IGF‐1 in ocular tissue in diabetes and antagonistic effect of somatostatins, (ii) the known effect of IGF‐1 in increasing lens aldose reductase and (iii) the lack of effect of somatostatins on diabetic hyperglycaemia, the latter enabling a differentiation to be made between effects of hyperglycaemia per se and site(s) of IGF‐1/somatostatins. All four metabolites studied showed a significant restoration towards the normal control level after 7 days of treatment with AGP and SMS, and AGP was more effective on levels of GSH and ATP. A significant correlation was found between GSH and ATP across all groups at 7 days treatment. The redox state changes in diabetes include both NADP+/NADPH and NAD+/NADH in the conversion of glucose to sorbitol and via sorbitol dehydrogenase to fructose with a linked decrease in ATP formation via NAD+/NADH regulation of the glycolytic pathway. The interlinked network of change includes the requirement for ATP in the synthesis of GSH. The present study points to possible loci of action of somatostatins in improving metabolic parameters in the diabetic rat lens via effects on aldose reductase and/or glucose transport at GLUT 3.     

山梨醇增加糖尿病患者腰椎管狭窄症炎性反应因子的表达

目的探讨糖尿病腰椎管狭窄患者黄韧带增生肥厚的发生机制。方法 24例糖尿病和20例非糖尿病的腰椎管狭窄患者列为研究对象,观测黄韧带标本结构,D-Sorbitol/Xylitol试剂盒检测山梨醇水平。体外实验中使用小鼠成纤维细胞(NIH3T3)细胞系,用Western blot及q PCR分别检测高糖培养条件及醛糖还原酶抑制剂(ARI):依帕司他(EP)作用对细胞炎性反应因子及TGF-β表达水平的影响。结果糖尿病组较非糖尿病组的山梨醇水平更高、黄韧带平均厚度更大、标本弹力纤维降解、胶原纤维增生更为显著、免疫组化CD68阳性染色率更高(P0.01);体外实验中,NIH3T3细胞系在高糖培养与正常糖浓度培养相比山梨醇、促炎性细胞因子和TGF-β表达水平更高,而山梨醇、促炎性细胞因子和TGF-β增高的表达水平可被醛糖还原酶抑制剂所抑制并且呈剂量依赖(P0.05)。结论糖尿病腰椎管狭窄患者黄韧带中山梨醇水平显著增高,进而促进炎性反应因子及纤维化相关因子TGF-β表达增加,使得黄韧带炎性增生。     

Risk factors for cataract in Chinese patients with type 2 diabetes: evidence for the influence of the aldose reductase gene

There is evidence that the development of retinopathy in type 2 diabetes is associated with a microsatellite polymorphism at 5' of the aldose reductase gene. The study examined whether cataract was associated with clinical/metabolic factors and/or the microsatellite polymorphism using a cohort of consecutively recruited Hong Kong Chinese patients with type 2 diabetes (n=567). Amongst these patients, 157 (28%) had cataract. The patients with cataract were older in age and age at diagnosis and had longer diabetes duration than those without cataract (all at p<0.01). They also had higher systolic blood pressure (p<0.01), HbA1c (p<0.05) and fasting plasma glucose levels (p<0.01; all with adjustment for the significance). Moreover, we found that the patients with cataract over-presented the microsatellite allele Z (23 vs. 30%, p<0.01) and its genotypes (Z,Z+Z,non-Z; 38 vs. 50%, p<0.01), but under-presented the allele Z-4 (8.3 vs 4.8%, p<0.05) and its genotypes (Z-4, Z-4+Z-4,non-Z-4; 16 vs. 10%, p<0.05). Using multiple logistic regression analysis (R2=0.25, p<0.01), we found that the presence of cataract was correlated positively with age, but inversely with the presence of allele Z-4. In conclusion, our data indicate that the occurrence of cataract is common in the Chinese type 2 diabetes population, with age and the aldose reductase gene as important determinants.     

Synthetic liver X receptor agonist T0901317 attenuates high glucose-induced oxidative stress,mitochondrial damage and apoptosis in cardiomyocytes

The aim of the present study was to investigate the protective effects of T0901317 (T0), a potent agonist of liver X receptors (LXRs), on high glucose-induced oxidative stress and apoptosis in H9c2 cardiac cells. Exposure of H9c2 cells to high glucose alone, not only caused a significant increase in apoptosis and reactive oxygen species (ROS) generation, but also led to a decrease in mitochondrial membrane potential (ΔΨm), release of cytochrome c, decrease in Bcl-2, increase in Bax expression and the activation of caspase-3, caspase-9, poly (ADP-ribose) polymerase (PARP) and nuclear factor (NF)-κB. However, pretreatment with T0 effectively decreased apoptosis, reduced the levels of ROS, abrogated ΔΨm, inhibited cytochrome c release and NF-κB activation, increased Bcl-2 and decreased Bax expression. In conclusion, our data suggest that T0 exerts protective effects against high glucose-induced apoptosis in H9C2 cardiac muscle cells via inhibition of ROS production, mitochondrial death and NF-κB activation.